Peptide plasminogen activators

Abstract

Novel polypeptide compositions based on the amino acid sequence of tissue plasminogen activator (tPA) are provided having improved properties over natural tissue plasminogen activator. Particularly, enhanced specific activity, reduced response to inhibition by plasminogen activator inhibitor, fibrin stimulation of plasminogenolytic activity and/or enhanced affinity to fibrin surfaces are provided by modifying one or more loci by deletions or substitutions. One or both of the N- or C-termini may be modified.

What is claimed is: 
     
       1. A human tissue plasminogen activator capable of dissolving clots having lysine 277 substituted with another amino acid, and further comprising a deletion of from 3 to 25 amino acids from the C-terminus. 
     
     
       2. A pharmaceutical composition comprising a human tissue plasminogen activator of claim 1. 
     
     
       3. A nucleic acid molecule encoding a human tissue plasminogen activator of claim 1. 
     
     
       4. A vector comprising the nucleic acid sequence of claim 3. 
     
     
       5. A method of making the vector of claim 4, comprising: (a) isolating said nucleic acid sequence; and   (b) inserting said nucleic acid sequence into an expression vector such that it would be expressed in an appropriate host cell.   
     
     
       6. A host cell comprising the nucleic acid sequence of claim 3. 
     
     
       7. A method of making a human tissue plasminogen activator according to claim 1, comprising: (a) culturing a host cell comprising a nucleic acid encoding said human tissue plasminogen activator; and   (b) isolating the protein.   
     
     
       8. A human tissue plasminogen activator of claim 1, further comprising a substitution of at least one of the group consisting of asparagine 117, asparagine 184 and asparagine 448 with another amino acid. 
     
     
       9. A pharmaceutical composition comprising a human tissue plasminogen activator of claim 8. 
     
     
       10. A nucleic acid molecule encoding a human tissue plasminogen activator of claim 8. 
     
     
       11. A vector comprising the nucleic acid sequence of claim 10. 
     
     
       12. A method of making the vector of claim 11, comprising: (a) isolating said nucleic acid sequence; and   (b) inserting said nucleic acid sequence into an expression vector such that it would be expressed in an appropriate host cell.   
     
     
       13. A host cell comprising the nucleic acid sequence of claim 10. 
     
     
       14. A method of making a human tissue plasminogen activator according to claim 8, comprising: (a) culturing a host cell comprising a nucleic acid encoding said human tissue plasminogen activator; and   (b) isolating the protein.